High blood glucose likely causal for unspecified dementia
medwireNews: A Mendelian randomization analysis supports a causal role of high blood glucose in unspecified dementia, but not in Alzheimer’s disease or vascular dementia.
Researchers constructed a weighted allele score based on seven genetic variants strongly linked to plasma glucose levels in genome-wide association studies.
Among 125,875 study participants with a maximum 43 years of follow-up (median 10 years), those in the 95–100th percentile for this score had glucose levels 5.1% higher than those in the 0–24th percentile, and they were also 24% more likely to have developed unspecified dementia, after adjustment for age, sex and year of birth. By contrast, the score was not associated with Alzheimer’s disease or vascular dementia.
Marianne Benn (University of Copenhagen, Denmark) and co-researchers say this fits with what is known about the pathogenesis of the three subtypes.
Each 1 mmol/L increase in non-fasting glucose levels measured at baseline was associated with a significant 1.04-fold increased risk for unspecified dementia, but each genetically determined 1 mmol/L increase was associated with a markedly larger 2.40-fold risk increase.
Furthermore, among people with type 2 diabetes, those with unspecified dementia were less often taking oral diabetes medications than those with the other dementia subtypes, at 15% versus 22–33%.
Together this suggests that “poor glycaemic control might have contributed to disease risk in these individuals and that improved diabetes diagnosis and management may reduce this risk,” the team concludes in Diabetologia.
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